libssh2_channel_wait_closed - wait for the remote to close the channel
int libssh2_channel_wait_closed(LIBSSH2_CHANNEL *channel);
Enter a temporary blocking state until the remote host closes the named
channel. Typically sent after libssh2_channel_close(3) in order to
examine the exit status.
Return 0 on success or negative on failure. It returns
LIBSSH2_ERROR_EAGAIN when it would otherwise block. While
LIBSSH2_ERROR_EAGAIN is a negative number, it isn’t really a failure